syntheses, characterization, resolution, and biological...

Research ArticleSyntheses Characterization Resolution and Biological Studiesof Coordination Compounds of Aspartic Acid and Glycine

Temitayo Aiyelabola1 Ezekiel Akinkunmi2 Isaac Ojo1 Efere Obuotor3

Clement Adebajo4 and David Isabirye5

1Department of Chemistry Obafemi Awolowo University Ile-Ife Osun State Nigeria2Department of Pharmaceutics Obafemi Awolowo University Ile-Ife Osun State Nigeria3Department of Biochemistry and Molecular Biology Obafemi Awolowo University Ile-Ife Osun State Nigeria4Department of Pharmacognosy Obafemi Awolowo University Ile-Ife Osun State Nigeria5Department of Chemistry North-West University Mafikeng Campus Mmabatho South Africa

Correspondence should be addressed to Temitayo Aiyelabola tt1hayeyahoocom

Received 14 August 2016 Accepted 14 November 2016 Published 15 February 2017

Academic Editor Muhammad Amin

Copyright copy 2017 Temitayo Aiyelabola et al This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

Enantiomerically enriched coordination compounds of aspartic acid and racemic mixtures of coordination compounds of glycinemetal-ligand ratio 1 3 were synthesized and characterized using infrared and UV-Vis spectrophotometric techniques andmagneticsusceptibility measurements Five of the complexes were resolved using (+)-cis-dichlorobis(ethylenediamine)cobalt(III) chlo-ride (+)-bis(glycinato)(110-phenanthroline)cobalt(III) chloride and (+)-tris(110-phenanthroline)nickel(II) chloride as resolvingagents The antimicrobial and cytotoxic activities of these complexes were then determined The results obtained indicated thataspartic acid and glycine coordinated in a bidentate fashion The enantiomeric purity of the compounds was in the range of 2210ndash3210 with (+)-cis-dichlorobis(ethylenediamine)cobalt(III) complex as themore efficient resolving agentThe resolved complexesexhibited better activity in some cases compared to the parent complexes for both biological activities It was therefore inferredthat although the increase in the lipophilicity of the complexes may assist in the permeability of the complexes through the cellmembrane of the pathogens the enantiomeric purity of the complexes is also of importance in their activity as antimicrobial andcytotoxic agents

1 Introduction

The need for more potent antimicrobial and anticanceragents has led to increased attention given to coordina-tion compounds in recent times This is partly due to thereports of increased bacterio- and carcinostatic activities ofsome biologically active compounds upon chelation [1ndash5]A current challenge facing coordination chemists is that ofobtaining enantiomerically pure compounds [6ndash11] Since thepotential target receptor sites for pharmacological agents arebiopolymers with chiral subunits the activity of therapeuticagents may involve molecular recognition by these sitesthereby demanding high optical purity [12ndash17] Hence highenantiomeric purity is essential for the effectiveness of theseagents and it is therefore important that these agents are

enantiopure Research has shown that when an enantiomerof a racemic or enantiomerically enriched form is inactivethe potency of the active enantiomer is reduced similarto the concept of deliberate adulteration Such situationswere encountered with warfarin and ibuprofen [12 15ndash19]In some cases one of the enantiomers may have toxic sideeffects as typified by thalidomide Both enantiomers ofthalidomide have desirable sedative properties however the(minus)-enantiomer is teratogenic presenting toxic side effectsthat led to its withdrawal from the market [20 21]Thereforeall these problems dictate the need of these optically activecompounds as enantiopure compounds Resolution serves asaway of discriminating between enantiomers of coordinationcompounds and diastereoisomer formation is the primarytechnique used [22ndash30] There is no single resolving agent

HindawiBioinorganic Chemistry and ApplicationsVolume 2017 Article ID 2956145 15 pageshttpsdoiorg10115520172956145

2 Bioinorganic Chemistry and Applications

CH C

O

C

OH

O

+H3N

CH2

Ominus

Figure 1 Aspartic acid

CH C

H

O

Ominus+

NH3

Figure 2 Glycine

that can be considered universal Hence choosing the rightresolving agent for enantiomeric separation may be a her-culean task [13 27]

Previous workers have synthesized and reported somesignificant antimicrobial and cytotoxic activities of coordi-nation compounds of various amino acids [31ndash37] How-ever these studies on their enantiomerically enriched andpure forms are few [38] and as indicated above obtain-ing these compounds at high enantiomeric purity mayenhance their potency and reduce their toxicity Asparticacid (Figure 1) is one of such amino acids studied itpossesses three potential donor sites (one amine and twocarboxyl groups) [37 39 40] It is therefore capable ofcoordinating as a bi- tri- and monodentate and bridgingligand Thus a variety of geometries are possible with thisligand which may be studied by comparing the complexesit forms with a series of metal ions of the same valencyat relevant pH ranges [41ndash47] Hence in this work coor-dination compounds of aspartic acid (L1) and glycine (L2Figure 2) were synthesized and characterized The aspartatocomplexes were synthesized using asymmetric synthesis viachiral pool syntheses while ion exchange chromatographywas used in separating some of the compounds into theirgeometric isomers In determining the most active resolv-ing agent the predominant isomers were further resolvedusing (+)-cis-dichlorobis(ethylenediamine)cobalt(III) chlo-ride (+)-bis(glycinato)(110-phenanthroline)cobalt(III) chlo-ride and (+)-tris(110-phenanthroline)nickel(II) chlorideThe synthesized compounds and resolved complexes werethen screened for their in vitro antimicrobial activity andbrine shrimp lethality

2 Materials and Methods

21 General All reagents and solvents used were of analyticalgrade Melting points or temperatures of decompositionwere measured using open capillary tubes on a Gallenkamp(variable heater)melting point apparatusTheUV-Vis spectra

were obtained using a Genesis 10 UV-Vis spectrophotome-ter at the Central Science Laboratory Obafemi AwolowoUniversity Ile-Ife Nigeria The infrared spectra (KBr) wererecorded on a Genesis II FT-IR spectrophotometer at North-West University Mafikeng Campus South Africa Opticalrotations were measured using Atago Polax-2L polarimeterat the Department of Pharmaceutical Chemistry ObafemiAwolowo University Ile-Ife Magnetic susceptibility wasobtained using a Sherwood scientific balance Kwara StateUniversity Nigeria Antimicrobial activities of the com-plexes was determined at the Department of PharmaceuticsObafemi Awolowo University Ile-Ife Brine shrimp lethalitybioassay was carried out at theDepartment Biochemistry andMolecular Biology Obafemi Awolowo University Ile-Ife

The syntheses characterization and the antimicrobialstudies for the glycinato complexes have been reportedpreviously [33] However the cytotoxic activity is reportedhere for the first time

22 Syntheses of Complexes

221 Preparation Sodium Tris(aspartato)cuprate(II) Na[Cu(L1)3] Copper(II) sulphate anhydrous solution (312 g002M) was dissolved in 10mL of distilled water and warmeduntil a clear solutionwas obtained (+)ndashAspartic acid solution(811 g 006M) was dissolved in distilled water (25mL) andwarmed over a steam bath and Na2SO4 solution (071 g0005M) was added with stirring The copper sulphatesolution was then added and the mixture heated for 2 hourson a steam bath (pH of the reaction was 231) The solutionobtained was concentrated and allowed to cool overnightwith the formation of a precipitate The precipitate obtainedwas filtered washed with methanol and dried in an oven at60∘C Yield 662 g 660 dp 232∘C IR data (cmminus1) 33802922 2851 1666 1547 702 595 UV-Vis data (nm) 217 223238 262 499 517 Magnetic moment 120583eff (BM) 193

Similar methods of preparation were used for the follow-ing compounds

222 Sodium Tris(aspartato)manganese(II) Na[Mn(L1)3]Manganese(II) chloride solution (438 g 002M) was addedto (+)ndashaspartic acid solution (802 g 006M) and sodiumsulphate solution (071 g 0005M) gave sodium tris-asparta-tomanganese(II) as white precipitate pH of reaction 242yield 834 g 830 dp 287∘C IR data (cmminus1) 2920 16811506 779 549 UV-Vis data (nm) 217 259 283 298 550 544574 679 Magnetic moment 120583eff (BM) 530

223 Sodium Tris(aspartato)nickelate(II) Na[Ni(L1)3] Ni-ckel(II) chloride hexahydrate solution (232 g 001M) wasadded to (+)ndashaspartic acid solution (400 g 003M) andsodium chloride solution (058 g 001M) gave sodium tris-aspartatonickelate(II) as fine green crystals pH of reaction237 yield 381 g 8807 dp 265∘C IR data (cmminus1) 34972994 1527 751 595 UV-Vis data (nm) 241 310 325 343 541820 Magnetic moment 120583eff (BM) 283

Bioinorganic Chemistry and Applications 3

224 Sodium Tris(aspartato)cobaltate(II) Na[Co(L1)3] Co-balt(II) chloride hexahydrate solution (214 g 001M) wasadded to (+)ndashaspartic acid solution (401 g 003M) andsodium chloride solution (058 g 001M) gave sodium tris-aspartatocobaltate(II) as purple crystals pH of reaction 235yield 343 g 6864 dp 265ndash267∘C IR data (cmminus1) 34042853 1654 1547 724 598 UV-Vis data (nm) 223 241 247 307484 505 Magnetic moment 120583eff (BM) 504

225 SodiumTris(aspartato)cadmium(II) Na[Cd(L1)3] Cad-mium(II) chloride monohydrate solution (312 g 002M)added to (+)ndashaspartic acid solution (811 g 006M) and(058 g 001M) sodium chloride solution gave sodium tris-aspartatocadmium(II) as a white precipitate pH of reaction244 yield 621 g 6260 dp 220ndash222∘C IR data (cmminus1)3547 3453 2890 1684 1460 776 599 UV-Vis data (nm) 217238 280 295 Magnetic moment 120583eff (BM) 000

226 Sodium Tris(glycinato)cobaltate(II) Na[Co(L2)3] Co-balt(II) chloride hexahydrate solution (251 g 001M) wasadded to glycine solution (229 g 003M) and sodium chlo-ride solution (058 g 001M) gave sodium tris-glycinato-cobaltate(II) as pink crystals pHof reaction 245 yield 184 g616 dp 223∘C IR data (cmminus1) 3428 2834 1621 1454 672509 UV-Vis data (nm) 220 226 256 520 667 682 Magneticmoment 120583eff (BM) 520

227 Bis(glycinato)copper(II) Complex [Cu(L2)]2 Copper(II)chloride anhydrous solution (162 g 001M) added to glycine(229 g 003M) and sodium sulphate solution (071 g0005M) gave bis(glycinato)copper(II) complex as blue pre-cipitate pH of reaction 259 yield 201 g 6700 dp 198∘CIR data (cmminus1) 3333 2913 1632 1416 695 501 UV-Vis data(nm) 262 620 632 Magnetic moment 120583eff (BM) 153

23 Resolution of the Geometrical Isomers Complexes of L1and L2 namely Na[Co(L1)3] Na[Cu(L1)3] Na[Ni(L1)3][Cu(L2)]2 and Na[Co(L2)3] were separated into their geo-metric isomers using an adaptation of the method describedby Glodjovic et al (2005) [48]

231 SodiumTris(aspartato)cobaltate(II) Na[Co(L1)3] Sodiumtris(aspartato)cobaltate(II) (283 g 0005M) was loaded ontoa column containing Dowex X 50 (200ndash400 mesh) anionexchange resin (chloride ion form) The column was washedwith water and eluted with 01M NaClO4 Two bands werecollected and their eluates concentrated and left to crystallizeThe crystals were thereafter washed and filtered First elutedisomer (pink) yield 108 g 3816 dp 261ndash263∘C UV-Vis(nm) 220 238 245 332 340 344 510 Second eluted isomer(blue) yield 052 g 1837 dp 265∘C UV-Vis (nm) 226232 246 336 340 346 514

A similar method was used for the following compounds

232 SodiumTris(aspartato)cuprate(II) Na[Cu(L1)3] Sodiumtris(aspartato)cuprate(II) (242 g 0005M) gave only one

band (blue) Yield 182 g 7521 dp 230∘C UV-Vis (nm)222 232 249 250 254 340 356 974

233 SodiumTris(aspartato)nickelate(II) Na[Ni(L1)3] In so-dium tris(aspartato)nickelate(II) (245 g 0005M) one bandwas observed (green) Yield 166 g 6782 dp 225∘C UV-Vis (nm) 444 648 980

234 Sodium Tris(glycinato)cobaltate(II) Na[Co(L2)3] Insodium tris(glycinato)cobaltate(II) (305 g 001M) twobands were obtained First eluted isomer (purple) yield187 g 6131 dp 261ndash263∘C UV-Vis (nm) 360 444 567Second eluted isomer (light pink) yield 021 g 689 dp265∘C UV-Vis (nm) 290 386 665

235 Bis(glycinato)copper(II) [Cu(L2)2]2 Bis(glycinato)cop-per(II) [Cu(L2)2]2 (311 g 001M) column eluted with watergave blue eluant Yield 192 g 63 dp 212∘C UV-Vis (nm)296 386 628 When eluted with 01M NaClO4 gave a violeteluant Yield 012 g 7 dp 221∘C UV-Vis (nm) 232 290386 637980

24 Preparation of Resolving Agents

241 cis-Dichlorobis(ethylenediamine)cobalt(III) Chloride Thesynthesis of cis-dichlorobis(ethylenediamine)cobalt(III) chlo-ride was carried out using an adaptation of the methoddescribed by Moriguchi (2000) [49] Cobalt(II) chloride-6-hydrate (24 g 01M) was dissolved completely in distilledwater (35mL) Anhydrous ethylenediamine (15 g 02M) in50mL of water was then added Hydrogen peroxide (12mL)was added dropwise with stirring The oxidized solutionwas cooled in ice and 12mL of concentrated HCl wasadded with stirring A dark ruby red solution was formedThe solution was then concentrated in a water bath andcooled Dark green crystals were obtained The crystals werethereafter dissolved in methanol solution filtered and driedin an oven at 100∘C Yield 2326 g 8223 The green trans-dichlorobis(ethylenediamine)cobalt(III) chloride obtainedwas then dissolved in a minimum amount of water heatedand evaporated to dryness to give a glassy deep violet productThis was filtered and washed with iced cold water to obtain aviolet powder of cis-dichlorobis(ethylenediamine)cobalt(III)chloride Yield 2131 g 7534 IR (cmminus1) 3444 3230 31042903 2012 1612 1099 938 801 UV-Vis (nm) 222 245 342489 609

242 Bis(glycinato)(110-phenanthroline)cobalt(III) ChlorideA solution of 110-phenanthroline (44 g 002M) and glycine(30 g 004M) in water (50mL) was added to cobalt(II)chloride-6-hydrate (583 g 002M) solution with stirringHydrogen peroxide was added gradually to the dark orangesolution with vigorous stirringThe suspension obtained wasconcentrated by heating at 65∘C and cooled to obtain crystalswhich were filtered and dried Yield 823 g 8920

The product obtained 460 g 001M was poured ontoa cation-exchange resin column (Dowex 50W-X8 200ndash400mesh anion exchange resin chloride ion form) The orange


solution of [Co(gly)2phe]Cl was obtained by eluting with020MKBr solution It was then concentrated at 70∘C cooledand filtered The residue was dissolved in methanol and thesolution was filtered The crude complex was obtained bythe addition of acetone to the filtrate Recrystallization wasachieved by dissolving it in a minimum amount of waterto which methanol-acetone (1 1) mixture was added Thissolution was allowed to stand in a refrigerator overnightThe orange crystals deposited were filtered and washed withmethanol-acetone (1 2)mixture and dried in a vacuum ovenYield 286 g 6263 IR (cmminus1) 3001 2858 2721 2650 18701685 1596 1507 1417 1304 1245 1149 983 893 UV-Vis (nm)224 238 244 507 618

243 Tris(110-phenanthroline)nickel(II) Chloride A solutionof 110-phenanthroline (650 g 003M) was added to a solu-tion of nickel(II) chloride (245 g 001M) with stirring Theresulting solution was heated over a water bath until a scumwas observedThe product was then left to crystallize and thecrystals obtained were filtered washed with methanol anddried Yield 449 g 6524 IR (cmminus1) 3397 3230 3104 20121612 1081 944 807 UV-Vis 222 232 244 342 521 623

25 Resolution of Resolving Agents

251 Resolution of cis-Dichlorobis(ethylenediamine)cobalt(III)Chloride Potassium antimonyl-D-tartrate hydrate (674 g001M) was dissolved in 10mL of water with warming andcis-[Coen2Cl2]Cl (596 g 002M) dissolved in 20mL of waterwas added The solution obtained was heated to 80∘C withstirring for 45min A pale violet precipitate was formed Theproduct was isolated by filtration washed with ethanol anddiethyl ether and dried in a vacuum oven at 60∘C Yield711 g 7861 The diastereoisomer (521 g 0005M) obtainedwas added with stirring to an aqueous slurry of potassiumchloride (052 g 0005M) Methanol was then added to pre-cipitate the cis-dichlorobis(ethylenediamine)cobalt(III) chlo-ride The residue obtained was recrystallized with methanoland acetone Optical rotation was constant after two recrys-tallizations Yield 093 g 6524 [120572]589 = +87∘ The generalequations for the reactions are shown in

4CoCl2 sdot 6H2O + 8en +H2O2

997888rarr 4 [Coen2 (OH)H2O]Cl2

(1)

119905119903119886119899119904- [Coen2 (OH)H2O]Cl2 + 2HCl

997888rarr Coen2Cl2Cl sdotHCl + 2H2O(2)

119905119903119886119899119904- [Coen2Cl2]Cl 997888rarr 119888119894119904- [Coen2Cl2]Cl (3)

2 119888119894119904- [Coen2Cl2]Cl + K2 [Sb2 (119889-tart)2]

997888rarr (+) - [Coen2Cl2]2 [Sb2 (119889-tart)2] + 2KCl(4)

(+) - [Coen2Cl2]2 [Sb2 (119889-tart)2]

997888rarr 2 (+) - [Coen2Cl2]Cl + K2 [Sb2 (119889-tart)2]

(grind with KCl)

(5)

252 ResolutionofBis(glycinato)(110-phenanthroline)cobalt(III)Chloride Potassium antimonyl-D-tartrate hydrate (641 g001M) was dissolved in 10mL of water with warmingA solution of the racemic mixture of bis(glycinato)(110-phenanthroline)cobalt(III) chloride (902 g 002M) dis-solved in 20mL of water was then added and stirred Thediastereomer which was deposited was filtered and washedwith amethanol-acetonemixture (1 1) and then acetoneThediastereomer was recrystallized by dissolving in a minimumquantity of water followed by gradual addition of methanolto produce turbidity and then cooled in ice to obtain crystalswhich were filtered washed and dried

A solution of the diastereomer (681 g 0005M) in aminimum amount of water was added to potassium chloride(052 g 0005M) with vigorous stirring A methanol-acetone (1 2) mixture was added to precipitate (+)-bis(glycinato)(110-phenanthroline)cobalt(III) chloride Thiswas filtered and dried Recrystallization was carried outwith a methanol-acetone (1 2) mixture Optical rotation wasconstant after two recrystallizations Yield 138 g 6211[120572]589 = +138∘

253 ResolutionofTris(110-phenanthroline)nickel(II) ChlorideA similar method as described in Section 251 was usedPotassium antimonyl-D-tartrate hydrate (324 g 0005M)was dissolved in 10mL of water with warming A solutionof the racemicmixture of tris(110-phenanthroline)nickel(III)chloride (454 g 001M) dissolved in 20mL of water wasthen added The diastereomer was recrystallized by dissolv-ing in a minimum quantity of water followed by gradualaddition of methanol to produce turbidity and then cooledin ice to obtain crystals that were filtered washed anddried A solution of the diastereomer (921 g 0005M) in aminimum amount of water was added to potassium chlo-ride (051 g 0005M) with vigorous stirring A methanol-acetone (1 2) mixture was added to precipitate tris(110-phenanthroline)nickel(II) chloride as pink crystals This wasfiltered and dried Recrystallization was carried out withmethanol-acetone (1 2) mixture Optical rotation was con-stant after two recrystallizations Yield 187 g 5421 [120572]589= +800∘

26 Resolution ofCompounds Thegeometric isomer of higheryield which was invariably the first eluted isomer forcomplexes Na[Co(L1)3] Na[Co(L2)3] Na[Cu(L1)3] andNa[Ni(L1)3] was resolved using dichlorobis(ethylenedia-mine)cobalt(III) chloride and bis(glycinato)(110-phenan-throline)cobalt(III) chloride as resolving agents using a simi-lar procedure as described in Section 253 Attempt was alsomade to use tris(110-phenanthroline)nickel(II) chloride asa resolving agent The general equations of reactions using


(+)-dichlorobis(ethylenediamine)cobalt (III) chloride aregiven in

Na [ML3] + (+) - [Coen2Cl2]Cl

997888rarr (+) - [Coen2Cl2] (+) - [ML3](6)

(+) - [Coen2Cl2] [ML3] +NaCl

997888rarr (+) -Na [ML3] + (+) - [Coen2Cl2]Cl(7)

27 Resolution Using (+)-cis-Dichlorobis(ethylenediamine)co-balt(III) Chloride

271 Na[Co(L1)3] First Eluted Isomer Sodium tris(asparta-to)cobaltate(II) (239 g 0005M) and (+)-dichlorobis(ethyl-enediamine)cobalt(III) chloride (147 g 0005M) Yield188 g 7866 [120572]589 = +36∘ ee = 2831

272 Na[Cu(L1)3] Sodium tris(aspartato)cupperate(II) (241 g0005M) and (+)-dichlorobis(ethylenediamine)cobalt(III) chlo-ride (157 g 0005M) Yield 158 g 6556 [120572]589 = +4750∘ee = 3210

273 Na[Ni(L1)3] Sodium tris(aspartato)nickelate(II) (236 g0005M) and (+)-dichlorobis(ethylenediamine)cobalt(III)chloride (153 g 0005M) Yield 153 g 6483 [120572]589 =+3550∘ ee = 2960

274 Na[Co(L2)3] First Eluted Isomer (1EI) Sodium tris(gly-cinato)cobaltate(II) (152 g 0005M) and (+)-dichlorob-is(ethylenediamine)cobalt(III) chloride (144 g 0005M)Yield 068 g 4274 [120572]589 = +4200∘

28 Resolution Using Bis(glycinato)(110-phenanthroline)co-balt(III) Chloride

281 Na[Co(L1)3] First Eluted Isomer Sodium tris(asparta-to)cobaltate(II) (237 g 0005M) and (+)-bis(glycinato)(110-phenanthroline)cobalt(III) chloride (319 g 0005M) Yield145 g 6118 [120572]589 = +34∘ ee = 2310

282 Na[Cu(L1)3] Sodium tris(aspartato)cupperate(II) (238 g0005M) and (+)-bis(glycinato)(110-phenanthroline)co-balt(III) chloride (294 g 0005M) Yield 142 g 5966[120572]589 = +4700∘ ee = 2210

283 Na[Ni(L1)3] Sodium tris(aspartato)nickelate(II) (236 g0005M) and (+)-bis(glycinato)(110-phenanthroline)co-balt(III) chloride (299 g 0005M) Yield 174 g 7373[120572]589 = +3200∘ ee = 2333

284 Na[Co(L2)3] First Eluted Isomer Sodium tris(glycina-to)cobaltate(II) (159 g 0005M) and (+)-bis(glycinato)(110-phenanthroline)cobalt(III) chloride (301 g 0005M) Yield049 g 3133 [120572]589 = +4025∘

29 Resolution Using (+)-Tris(110-phenanthroline)nickel(II)Chloride Attempt was made to resolve the complexesusing (+)-tris(110-phenanthroline)nickel(II) chloride atcomplex resolving agent ratio of 2 1 However for all thecomplexes the analysing lens was blurred and no rotationwas observed

210 Antimicrobial Activity Using Disc Diffusion Assay Thestrains used were Escherichia coli NCTC 8196 Pseudomonasaeruginosa ATCC 19429 Staphylococcus aureus NCTC 6571Proteus vulgaris NCIB Bacillus subtilis NCIB 3610 and onemethicillin-resistant S aureus clinical isolate for bacteriaand C albicans NCYC 6 for fungi The standard strainswere from stocks of culture collections maintained at thePharmaceutics Laboratory Obafemi Awolowo UniversityIle-Ife The bacteria were maintained on nutrient agar slantsand fungi on Sabouraud Dextrose Agar slants at 4∘C andsubcultured monthly Each test agent (20mg) was dissolvedin 1mL sterile distilled water boiled gently on a Bunsen flameDiscs of Whatman No 1 filter paper (120593 6mm) were soakedwith 2 drops of the test agent using a sterile Pasteur pipetteand allowed to dry at room temperature

Two colonies of a 24-hour plate culture of each organismwere transferred aseptically into 10mL sterile distilled waterin a test tube and mixed thoroughly using an electric shakerfor uniform distribution A sterile cotton swab was thenused to spread the resulting suspension uniformly on thesurface of oven-dried Mueller Hinton Agar (Oxoid) andSabouraud Dextrose Agar plates (Sterillin) for bacteria andfungi respectively These were incubated for an hour at 37∘and 25∘C for bacteria and fungi respectively Sterile forcepswere used to aseptically place each of the discs on the agarplates and the plates were then refrigerated for 30min at 4∘Cfollowing which the inoculated plates were incubated at 37∘Cfor 24 hours for bacteria strains and 25∘C for 72 hours for thefungal strain Antimicrobial activity was evaluated by notingthe zones of inhibition against the test organisms [50]

211 Cytotoxicity Bioassay The procedure used was modifiedfrom the assay described by Solis et al (1993) [51] Brineshrimps (Artemia salina) were hatched using brine shrimpeggs in a conical shaped vessel (1 L) filledwith sterile artificialseawater under constant aeration for 48 h After hatchingactive nauplii free from egg shells were collected from abrighter portion of the hatching chamber and used for theassay Ten nauplii were drawn through a Pasteur pipette andplaced in each vial containing 45mgL brine solution Ineach experiment different volumes of sample were added to45mL of brine solution to give different concentrations (2040 60 80 and 100 120583gmL) and maintained at room tem-perature for 24 h under the light The surviving larvae werecounted Experiments were conducted along with control(vehicle treated) of the test substances in a set of three tubesper dose

212 Statistical Analysis The in vitro antimicrobial analysisdata was analysed using one-way ANOVA by SPSS 16 (Sta-tistical Package for the Social Sciences) for Windows Mean


Table 1 Relevant IR bands for the ligands and compounds

Compound ]s(NndashH) (cmminus1) ]asy(COOminus) (cmminus1) ]sy(COOminus) (cmminus1) ](MndashN) (cmminus1) ](MndashO) (cmminus1)Aspartic acid 3380w 1650s 1583sGlycine 3119br 1615sNa[Cu(L1)3] 3380br 1666br 1547s 595br 682mNa[Cd(L1)3] 35473452br 1684m 1512br 599s 658sNa[Ni(L1)3] 3497br mdash 1527w 595s 629sNa[Co(L1)3] 3404wbr 1654s 1547s 598s 668sNa[Mn(L1)3] mdash 1681s 1506s 549s 601s[Cu (L2)2]2 3333br 1632br 1416br 501s 695sNa[Co(L2)3] 3428br 1621s 1454s 509s 672sw weak m medium s strong br broad

separation test between treatments was performed usingDuncanrsquos multiple range tests P value le 005 was consideredstatistically significant

The brine shrimp mortality data was subjected to ProbitRegression Analysis (Finney 1971) using the United StatesEnvironmental Protection Agency (USEPA) Probit Analysissoftware program version 15

3 Results and Discussion

31 Characterization of Synthesized Complexes

311 Aspartato Complexes The infrared spectrumof asparticacid showed a broad band at 3380 cmminus1 that was assignedto the ](NndashH) absorption stretching frequency On coor-dination this was shifted to higher wave number with theexception of the manganese and copper complexes [52ndash54]The absence of a distinct band for the manganese complexwas adduced to the hydrogen bonding between the hydrogenatom of the amino substituent and the uncoordinated oxygenatom of the ligand [55 56] For reasons that were not quiteevident the spectrum of the copper complex exhibited noshift in the ](NH2) absorption when compared with that ofthe ligand However shifts in the carbon-nitrogen absorptionfrequency and appearance of new bands that could beascribed to the metal-nitrogen band in the spectrum ofthe complex suggested that the nitrogen atomrsquos lone pairof electrons were used for coordination in the complex(Table 1) Based on this it was suggested that there wasprobable elongation of themetal-nitrogen bond substantiallyfor the ](NH2) absorption to occur at the same position Fromprevious studies the axial bonds of octahedrally coordinatedcopper(II) complexes are of higher energy compared with theequatorial bonds consequently bonding at the axial positionis elongated at one of the apical regions of such complexand this is attributable to the Jahn-Teller distortion [57] It isproposed therefore that the amino substituent is positionedat the apical region in the complex this type of arrangementmay be assigned as the trans-aminecis-carboxylate isomerof the complex (Figure 3) [52 58] Further buttressing thispoint of view is the fact that amino acids exist as zwitterionsin crystalline form with a positively charged ammonium ion

with a weak ](NndashH) band Similar to that obtained for thecopper complex evidence for coordination to the metal ionvia the nitrogen atom of the ligand was also given by theshifts in the carbon-nitrogen absorption band frequencieson coordination for all the other complexes [52] This wascorroborated by the observed MndashN absorption frequency inthe region 549ndash599 nm which was absent in the spectrumof the ligand [53 59] Intense bands at 1650 and 1583 cmminus1in the spectrum of the ligand were attributed to COOminusasyand COOminussy stretching frequencies respectively [52 55] Oncomplexation these were shifted to higher and lower wavenumbers respectively (Table 1) suggesting that the oxygenatom of the carboxylate group of the ligand was used forcoordination [37 52] The nickel complex showed no clearlydefined band and thismay be attributable to the overlap of thendashNH2 bending frequency [52] The metal oxygen absorptionfrequency was observed in the region 601ndash682 nm (Table 1)further supporting coordination via the oxygen atom ofthe ligand [52ndash54] Sharp extended bands in the region of3700 and 3880 cmminus1 suggest ndashOH stretching absorption withhydrogen bonding attributed to ndashOH of the uncoordinatedcarboxylic acid of the side chain of the ligand [52 60 61]Thiswas corroborated by the presence of sharp extended bandsin the 1730 cmminus1 region in the spectrum of the complexesattributable to free uncoordinated carbonyl stretching fre-quencywith hydrogen bonding As a consequence this servesas an indication of the nonparticipation of the carboxylic acidgroup of the side chain in binding [56]

The electronic spectrum for aspartic acid exhibited threeabsorption bands at 196 212 and 232 nm assigned as the119899 rarr 120590lowast 119899 rarr 120587lowast and 120587lowast rarr 120587lowast transitions and ascribed tointraligand electronic transitions On coordination howevershifts were observed in these bands in addition to new d-dtransition bands (Table 2) [33 52 53]These and themagneticmoment of the complexes were used to propose probablegeometry of the complexes The electronic spectrum of theCu(II) complex showed a well resolved band at 499 nm anda weak band at 517 nm typical for a tetragonally distortedoctahedral configuration and may be assigned to 2B1g rarr2A1g and

2B1g rarr2Eg transitions Its magnetic moment value

of 193 BM is indicative of amononuclear octahedral complexThis is in agreement with what was proposed by previous


Table 2 Electronic spectra bands for the ligands and complexes

Compound Band I (nm) Band II (nm) Band III (nm) d-d (nm)Aspartic acid 196 212 232Glycine 199 211 244Na[Cu(L1)3] 217 223 238 262 499 517Na[Cd(L1)3] 217 238 280 295 mdashNa[Ni(L1)3] 241 310 325 343 541 820Na[Co(L1)3] 223 241 247 307 484 505Na[Mn(L1)3] 217 259 283 298 550 574 679[Cu (L2)2]2 mdash 265 mdash 620 632Na[Co(L2)3] 220 266 256 520 667 682

M

O

O

CHC

C

CH

CCH

O

O

O

R

R

O

R

H2N

H2N

NH2

Figure 3 trans-Aminecis-carboxylate isomer (R = ndashCH2COOH)

workers [33 62ndash66] No d-d absorption band was observedin the spectrum of the cadmium(II) complex A magneticmoment of zero was obtained indicating that there was nounpaired electron This is in accord with what was obtainedby Anacona et al (2005) [33 67]The spectrum for the Ni(II)complex showed d-d bands at 541 and 820 nm which wereassigned to spin allowed transitions of 3A2g(F) rarr

5T1g(F)and 3A2g(F) rarr

5T1g(P) suggestive of an octahedral geometry[57] The magnetic moment of 283 BM indicated twounpaired electrons per nickel ion which further validates theoctahedral geometry for the complex with interconversion ofstereochemistries or dimerization [33] The Co(II) complexexhibited well resolved band at 484 nm and a strong bandat 505 nm which were assigned to 4T1g(F) rarr

4T2g(F) and4T1g(F) rarr

4T1g(P) indicative of a high-spin octahedralgeometry The magnetic moment of 504 BM is indicative ofthree unpaired electrons including orbital contribution andis in agreement with the proposed octahedral geometry (Fig-ure 4) [33 62 68] The Mn(II) complex exhibited low energybands at 550 and 574 nm consistent with a six-coordinateoctahedral geometry (Figure 4) The complex had a high-spin magnetic moment of 530 BM The zero crystal fieldstabilization energy of the high-spin configuration confers noadvantage of any particular stereochemistry for Mn(II) ionHowever the value obtained agrees well with other publishedwork for an octahedral geometry for a d5 Mn(II) system[62 63 67]

M

NO

OCCH

C

CH

CCH

R

R

R

O

O

OOH2N

NH2

H2

minus

Figure 4 The proposed structure for the tris-chelate complexes R= ndashH glycinato complexes ndashCH2COOH aspartato complexes

312 Glycinato Complexes The comparison of the infraredspectra of glycine and the complexes provided evidence ofcoordination of the metal ion with the ligand via the nitrogenatom of its amino substituent This is because the ndashNH2stretching frequency for the ligand at 3119 cmminus1 was shiftedin the complexes hypsochromically to 3333 and 3428 nm forthe Cu(II) and Co(II) complex respectively This is in accordwith the concept of lone-pair donation of nitrogen atom ofthe ligand on coordination [52 69] The coordination of thenitrogen atom of NH2 was corroborated by the appearanceof new bands which were not present in the spectrum ofthe ligand at 501 and 509 cmminus1 ascribable to metal-nitrogenabsorption frequencies [53 59] The observed medium bandat 1112 cmminus1 in the free ligand was attributed to the ](CndashN) absorption and this blue-shifted on coordination [52]The asymmetric stretching vibration frequency observedat 1615 cmminus1 for the carboxylate ion was shifted to higherfrequencies with the complexes confirming coordination viathis functional group [52] For the symmetric stretch sharpextended bands were observed instead of distinct bandsThis has been reported to be due to the zwitterionic natureof the ligand in the crystalline form [52] New bands at695 and 672 cmminus1 were assigned to metal-oxygen absorptionfrequencies [33 53 59]

The absorption spectrum for the free ligand glycineexhibited bands at 199 211 and 244 attributed to 119899 rarr 120590lowast


M

N

O

O

OC

CH

C

CH

CCH

OR

R

R

O

O

mer-isomer

M

O

N

O

OC

CH

CH

C

CCH

RR

O

R

O

O

fac-isomer

NH2

H2NH2N

H2

H2

NH2

minusminus

Figure 5 The proposed structure for the geometric isomers for the tris-chelate complexes R = ndashH glycinato complexes ndashCH2COOHaspartato complexes

119899 rarr 120587lowast and120587lowast rarr 120587lowast transitionsThe visible spectrumof theCu(II) complex displayed bands at 620 and 632 nm assignedto 2B1g rarr

2A1g and 2B1g rarr2E1g transitions ascribed

to a square pyramidal geometry The magnetic moment of153 BM of the glycinato Cu(II) complex is indicative of anantiferromagnetic spin-spin interaction through molecularassociation with possible CundashCu interaction or dimerizationsimilar results have been reported for the copper(II)acetatecomplex [33 62] Hence these facts allowed the proposalof a dinuclear square pyramidal geometry for the complexThe Co(II) complex gave two well resolved absorptionbands which were assigned to 4T1g(F) rarr

4A2g(F) and4T1g(F) rarr

4T1g(P) transitions respectively consistent with asix-coordinate octahedral geometry (Figure 4)Themagneticmoment of 520 BMof the glycinatoCo(II) complex indicateda high-spin d7 system with three unpaired electrons whichcorroborates the proposed octahedral geometry (Figure 4)[33]

From previous studies the 120572-carboxylic acid group ofaspartic acid has been reported to have pK119886 of 209 the 120573-carboxylic acid group pk119886 of 386 and the NH+3 pK119886 of 982Hence in aspartic acidrsquos zwitterionic form at pH of sim3 onlythe 120572-carboxylic and the amino groups are available for bind-ing with metal ions [70 71] The pH range for synthesizingthe complexes in this study was within the range in asparticacidrsquos zwitterionic form (231ndash244) The results obtained forthe characterization of the complexes indicated that asparticacid coordinated in a bidentate fashion coordinating via thenitrogen of the ndashNH2 and the oxygen of the carboxylateion This result validates the coordination mode of asparticacid as a bidentate ligand [33 37 39] In addition it furthercorroborates the pH dependence for the available donoratoms in the ligand [37 39 40 72 73] Glycine similarlycoordinated via the same donor atoms as a bidentate ligand

32 Geometrical Isomers Two geometrical isomers wereobtained for Na[Co(L1)3] and Na[Co(L2)3] From previ-ous studies tris-chelate complexes exhibited two possiblegeometric isomers namely the facial cis-cis and meridional

cis-trans isomers It is suggested that the more readily elutedisomer is the cis-trans isomer This is because it has a lowerdipole moment compared to the cis-cis isomer and as such ismore readily eluted from the ion-exchange column [62 74]The separation of the geometric isomers for [Cu(L2)2] gavetwo isomers as well Dinuclear square planar complexes havebeen reported to exhibit cis and trans geometric isomers [75]In this case similar to the bis-chelate complexes the morereadily eluted isomer was ascribed to the trans isomer [74]No separation was observed on the ion-exchange columnfor Na[Cu(L1)3] and Na[Ni(L1)3] pointing to the fact thatgeometric isomers are diastereomers and may be separatedby physical meansTherefore it is probable that such isomersmay have been separated during preparation or purification[7 28 29 39 52 62]

According to Greenwood and Earnshaw (1997) the UV-Vis spectra of geometrical isomers are often diagnostic Fromthis viewpoint UV-Vis spectra of the geometric isomers forNa[Co(L1)3] [Cu(L2)]2 and Na[Co(L2)3] were obtainedThe spectrum of the second eluted isomer exhibited highermolar extinction coefficient for the 119889-119889 transition absorptionband than the corresponding first eluted isomer as evidentwith Na[Co(L1)3] first eluted isomer (120582max 510 nm 12057651040molminus1 dmminus3 cmminus1) and second eluted isomer (120582max 514 nm120576514 250molminus1 dmminus3 cmminus1) with Na[Co(L2)3] first elutedisomer (120582max 567 nm 120576567 30molminus1 dmminus3 cmminus1) and secondeluted isomer (120582max 665 nm 120576665 80molminus1 dmminus3 cmminus1)with [Cu(L2)]2 first eluted isomer (120582max 628 nm 12057662850molminus1 dmminus3 cmminus1) and second eluted isomer (120582max637 nm 120576637 70molminus1 dmminus3 cmminus1) Consequently the secondeluted isomer was assigned to the fac-isomer for Na[Co(L1)3]and Na[Co(L2)3] This is because of the centrosymmetricnature of the mer-isomer compared to the fac-isomer(Figure 5) [52 62 74] It was however assigned as the transisomer for [Cu(L2)]2 and the spectrum with d-d transitionbands with lower molar extinction coefficient as cis isomer[75]

33 Optical Activity The specific rotation of the synthe-sized compounds was determined and the result obtained


M

N

O

O

OC

CH

C

CH

CCH

OR

R

R

O

O

M

NO

OCCH

C

CH

CCH

R

R

R

O

O

OO

H2N

H2N

H2

H2

NH2

NH2

minusminus

Figure 6 The proposed structure for the optical isomer for the tris-chelate complexes R ndashH glycinato complexes ndashCH2COOH aspartatocomplexes

showed that the enantiomerically enriched compounds weredextrorotary isomers indicating primarily that the enan-tiomerically enriched complexes are in excess of the dex-trorotary isomer This is not totally unexpected as thecompounds were synthesized using asymmetric synthesis viachiral pool syntheses Previous researches have shown thatproducts obtained from such reactions are enantiomericallyenriched in favour of the chiral starting material [7 2938 76] In the case of the glycinato complexes the specificrotation was zero suggestive of a racemic mixture [1028 29] This may be a result of the nonchiral nature ofglycine

The mer-isomers of Na[Co(L1)3] and Na[Co(L2)3] thesynthesized complexes of Na[Ni(L1)3] and Na[Co(L1)3]were resolved using (+)-cis-dichlorobis(ethylenediamine)co-balt(III) complex and (+)-bis(glycinato)-110-phenantroline-cobalt(II) chloride as resolving agent (Figure 6) The specificrotation and enantiomeric excess of the resolved compoundswere determinedThe enantiomeric purity of the compoundswas in the range of 2210ndash2333 using bis(glycinato)-(110-phenanthroline)cobalt(II) complex and 2831ndash3210using (+)-cis-dichlorobis(ethylenediamine)cobalt(III) com-plex the better resolving agent Attempt to resolve the com-plexes using (+)-tris(110-phenanthroline)nickel(II) complexwas not successful According to Kirschner et al (1979) andLennartson (2011) tris(110-phenanthroline)nickel(II) com-plex is optically labile in aqueous solution Therefore itmay not be an efficient resolving agent [77 78] From astructural point of view we are unable to give reasons why(+)-cis-dichlorobis(ethylenediamine)cobalt(III) complex isthe preferred resolving agent It has however been reportedthat coordination compounds form diastereomeric com-plexes via intimate ion-pair formation [79ndash81] It is pro-posed consequently that chiral recognition may be said tohave been achieved through this mechanism Attempt toresolve [Cu(L2)]2 using column chromatography was unsuc-cessful thus suggesting the specificity of chiral resolvingagents

34 Antimicrobial Activities The in vitro antimicrobial activ-ities of the parent and resolved synthesized compounds are

presented in Table 3 The ligands and their parent Cu(II)complexes (Na[Cu(L1)3] and Cu(L2)2) were inactive againstall the tested microbes This is contrary to the establishedantimicrobial activity of copper and its complexes [82ndash85]Previous studies have proposed that one of the possiblemechanisms of antimicrobial activity of similar compounds isvia ligand exchange [31] It is suggested that as a result of thedistortion in the geometry for (+)-Na[Cu(L1)3] it may notbe well suited for the receptor site [1 3 31] Hence molecularrecognition of the complex by the receptor site of themicrobemay not be achieved as a consequence

The synthesized parent complex of Na[Ni(L1)3] and thecadmium aspartato complex also lacked antibacterial activitybut had similar moderate antifungal activity to acriflavine(Table 3) Also the complexes Na[Co(L1)3] Na[Mn(L1)3]and NaCo(L2)3 respectively had varied activities against themicrobes tested Comparing the activities ofNa[Co(L1)3] andNa[Mn(L1)3] showed that they both had similar moderateactivity against P vulgaris and were largely inactive againstE coli S aureus and B subtilis However the higher activityof the latter over the former against MRSA and that of theformer against Ps aeruginosa and C albicans may indicatethe antimicrobial specificity of the complexes tested Further-more the activities demonstrated by Na[Co(L1)3] against Pvulgaris and C albicans were greatly better than those ofNa[Co(L2)3] while the latter had highly better activity againstPs aeruginosa and MRSA and somewhat better activitiesagainst the other twoGram-negative bacteria tested (Table 3)Thismay indicate that although the ligands lack antimicrobialactivity somehow glycine contributes to the actualization ofthe broad spectrum antimicrobial activity of its coordinatedcompounds Since glycine is more lipophilic than asparticacid lipophilicity is possibly a contributing factor Lipophilic-ity that confers the ability to cross the membrane barrierhas been reported as a factor of biological activity includingantimicrobial activity [86ndash95] This suggests that chelationmay serve as a tool of obtaining potent antimicrobial agents[86ndash93]

(+)-cis-Dichlorobis(ethylenediamine)cobalt(III) com-plex gave better enantiomeric purity and was thereforethe resolving agent of choice Compared to the parent


Table3Antim

icrobialactiv

ities

ofthec

ompo

unds

Zone

ofinhibitio

n(sizem

easuredinclu

ded60m

mof

thefi

lterp

aper

disc)

Microorganism

Na[Cu

(L1) 3]

Na[Co(L 1) 3]

Na[Ni(L1) 3]

Na[Co(L 2) 3]

Na[Cd(L 1) 3]

Na[Mn(L 1) 3]

[Cu(L 2) 2]

Acrifl

avine

PR

PR

PR

PR

Ecoli

60

60

60

60

60

80plusmn09

90plusmn03

80plusmn01

60

60

60

200plusmn04

Psaeruginosa

60

60

110plusmn03

80plusmn02

60

60

202plusmn01

240plusmn04

60

80plusmn05

60

60

Pvulga

ris60

60

140plusmn05

60

60

60

90plusmn02

110plusmn06

60

140plusmn08

60

150plusmn06

Saureus

60

160plusmn03

60

120plusmn02

60

60

130plusmn05

60

60

80plusmn01

60

200plusmn02

Bsubtilis

60

60

90plusmn03

180plusmn08

60

60

131plusmn10

160plusmn03

60

80plusmn06

60

60

MRS

A60

60

60

80plusmn04

60

80plusmn05

150plusmn00

160plusmn02

60

200plusmn04

60

60

Calbicans

60

60

18plusmn02

240plusmn05

180plusmn05

90plusmn01

60

60

180plusmn05

60

60

190plusmn01

L 1aspartic

acidL2glycineP

parentcom

poun

dsof

Na[Cu

(L1) 3]Na[Co(L 1) 3]Na[Ni(L1) 3]Na[Co(L 2) 3]andNa[Cd(L 1) 3]R

parent

compo

undsrsquorespectiveresolvedform

sE

coliEscherich

iacoliNCT

C8196

PsaeruginosaPseudomonas

aeruginosa

ATCC

19429Pvulga

risP

roteus

vulga

risNCI

BSaureusStaphylo

coccus

aureus

NCT

C6571B

subtilis

BacillussubtilisNCI

B3610M

RSA

methicillin-resis

tant

Saureus

clinicalisolateC

albica

nsC

andida

albicans

NCY

C6


Table 4 Cytotoxic activity of the parent and resolved compounds

Compound LC50 (95 confidence Interval) (ugmL)

Na[Cu(L1)3]P 7492 (0003ndash19817)R 4691 (0225ndash1025)

Na[Co(L1)3]P 4576 (0001ndash1264)R 4550 (0001ndash1264)

Na[Ni(L1)3]P 4187 (0000ndash1304)R 8044 (0477ndash1749)

Na[Co(L2)3]P 7432 (0882ndash1492)R 4775 (minus)

L1 6942 (1007ndash13478)L2 13867 (2411ndash28421)K2Cr2O7 (Standard) 3377 (1479ndash4505)Values expressed as L50 values (95 confidence interval)P parent compound R resolved compound

compound the resolved Na[Cu(L1)3] demonstrated a greatlyhigher activity only against S aureus a Gram-positivebacterium (Table 3) The results in Table 3 supported thehypothesis of increased biological activity of the resolvedcompounds and may also indicate the importance ofchirality in the activity against S aureus [12 13 40 96]The resolved complex of Na[Co(L1)3] gave double the zoneof inhibition of the parent compound only against theGram-positive bacteria of S aureus and B subtilis and aslightly better activity against the fungus and MRSA Alsothe resolved Na[Ni(L1)3] showed slightly better activitiesonly against E coli and S aureus than the parent complexSimilarly the resolved NaCo(L2)3 showed slightly betteractivities against Ps aeruginosa P vulgaris and B subtilisthan the parent complex (Table 3) All these results alsosupported the better activity of the resolved compoundsand consequently the role of chirality in the demonstratedantimicrobial activity of coordinated compounds testedOn the other hand the activities of the parent compoundsof Na[Co(L1)3] against Ps aeruginosa and P vulgarisNa[Ni(L1)3] against the fungus and Na[Co(L2)3] against Saureus were higher than those of the resolved compounds(Table 3) An inactive enantiomer has been suggested as apotent antagonist for a receptor site consequently reducingthe efficacy of an optically active antimicrobial agent evenat high enantiomeric excess [12 13 40 96] These resultsalso may confirm the specificity of antimicrobial activitiesof the resolved compounds [12 13 40 96] Acriflavine thestandard drug had better activities against E coli and Saureus than all the tested synthesized compounds while someof the latter were better against some microbes The resultsobtained thus demonstrate the usefulness of resolution ofracemates and enantiomerically enriched compounds indrug development of antimicrobial agents of coordinatedcompounds

35 Cytotoxicity Brine shrimp lethality bioassay is a simplecytotoxicity test based on the killing ability of test compoundson a simple zoological organism brine shrimp (Artemiasalina) [97] The standard cytotoxic compound used was

K2Cr2O7 [98] The result obtained indicated that the com-plexes (parent and resolved) and the ligands elicited goodcytotoxic activity with LC50 values in the range of 4187and 13867 120583gmLminus1 (Table 4) According to Meyer et al(1982) compounds with LC50 lt 1000120583gmLminus1 are consideredsignificantly toxic [99] The resolved complexes with theexception of Na[Ni(L1)3] showed higher cytotoxicity thantheir respective parent complexes Furthermore the resolvedcomplexes and the two ligands employed aspartic acid andglycine elicited cytotoxic activities in a 2ndash4-fold range morethan the standard cytotoxic compound K2Cr2O7 Fromthe foregoing it can be argued that the resolution processenhanced the cytotoxic properties of the synthesized com-plexes (Table 4) Although the tested compounds exhibitedcytotoxic activity against a simple invertebrate organism theuse of appropriate human cell lines may be necessary forextrapolation of this finding to the mammalian system

4 Conclusion

It was concluded from this study that the antimicrobialactivity of the resolved complexes in some case was bettercompared to that of the parent synthesized complexes againstmost of the pathogens investigated It can further be con-cluded that complexation imparted strong cytotoxic activitieson the ligands and resolving the complexes improved onthese activities These results therefore stress the need todevelop the means for complete resolution of pharmacolog-ically active complexes in their enantiomerically enriched orracemic forms to obtain enantiopure compounds

Competing Interests

The authors declare that there are no competing interestsregarding the publication of this paper

References

[1] Z H Chohan M Arif M A Akhtar and C T SupuranldquoMetal-based antibacterial and antifungal agents synthesis


characterization and in vitro biological evaluation of Co(II)Cu(II) Ni(II) and Zn(II) complexes with amino acid-derivedcompoundsrdquo Bioinorganic Chemistry and Applications vol2006 Article ID 83131 13 pages 2006

[2] I Kostova ldquoPlatinum complexes as anticancer agentsrdquo RecentPatents on Anti-Cancer Drug Discovery vol 1 no 1 pp 1ndash222006

[3] E L Chang C Simmers and D A Knight ldquoCobalt complexesas antiviral and antibacterial agentsrdquoPharmaceuticals vol 3 no6 pp 1711ndash1728 2010

[4] A F Husseiny E S Aazam and J Al Shebary ldquoSynthesischaracterization and antibacterial activity of schiff-base ligandincorporating coumarin moiety and it metal complexesrdquo Inor-ganic Chemistry vol 3 pp 64ndash68 2008

[5] S Emami and S Dadashpour ldquoCurrent developments ofcoumarin-based anti-cancer agents in medicinal chemistryrdquoEuropean Journal of Medicinal Chemistry vol 102 pp 611ndash6302015

[6] E Meggers ldquoChiral auxiliaries as emerging tools for the asym-metric synthesis of octahedralmetal complexesrdquoChemistry vol16 no 3 pp 752ndash758 2010

[7] E Meggers ldquoMetal templated design from enzyme inhibitionto asymmetric catalysisrdquo in Proceedings of the 12th EuropeanBiological Inoganic Chemistry Conference Zurich Switzerland2014

[8] A M Sargeson ldquoOptical phenomenon metal chelatesrdquo inChelating Agents and Metal Chelates F P Dwyer and D PMellor Eds pp 183ndash232 Academic Press New York NY USA1965

[9] E Farkas and I Sovago ldquoMetal complexes of amino acids andpeptidesrdquo in Amino Acids Peptides and Proteins J S DaviesEd vol 35 pp 353ndash434 Royal Society of Chemistry LondonUK 2006

[10] HAmouri andAGruselle ldquoChirality and enantiomersrdquo inChi-rality in TransitionMetal Chemistry Molecules SupramolecularAssemblies and Materials pp 7ndash61 John Wiley amp Sons WestSussex UK 2008

[11] H Brunner ldquoChiral metal atoms in optically active organo-transition-metal compoundsrdquo Advances in OrganometallicChemistry vol 18 pp 151ndash206 1980

[12] G R Stephenson and J P Genet ldquoDesign of asymmetricsynthesisrdquo inAdvancedAsymmetric Synthesis G R StephensonEd pp 2ndash8 Chapman amp Hall London UK 1996

[13] L A Nguyen H He and C Pham-Huy ldquoChiral drugs anoverviewrdquo International Journal of Biomedical Science vol 2 pp85ndash100 2006

[14] M F Landoni and A Soraci ldquoPharmacology of chiralcompounds 2-arylpropionic acid derivativesrdquo Current DrugMetabolism vol 2 no 1 pp 37ndash51 2001

[15] E J Ariens ldquoStereoselectivity of bioactive agents generalaspectsrdquo in Stereochemistry and Biological activity of Drugs EJ Ariens W Soudijn and P B Timmermans Eds pp 11ndash33Blackwell Scientific Oxford UK 1983

[16] N M Davies and X V Teng ldquoImportance of chiralityrdquo in DrugTherapy and Pharmacy Practice Implication for Psychiatry vol1 no 3 of Advances in Pharmacy pp 242ndash252 2003

[17] J Patocka and A Dvorak ldquoBiomedical aspects of chiralmoleculesrdquo Journal of AppliedMedicine vol 2 pp 95ndash100 2004

[18] J H Lin and A Y H Lu ldquoRole of pharmacokinetics andmetabolism in drug discovery and developmentrdquo Pharmacolog-ical Reviews vol 49 no 4 pp 403ndash449 1997

[19] A Somogyi F Bochner and D Foster ldquoInside the isomers thetale of chiral switchesrdquo Australian Prescriber vol 27 no 2 pp47ndash51 2004

[20] J Hornback ldquoStereochemistryrdquo in Organic Chemistry pp 238ndash245 Brooks and Cole 1998

[21] R Noyori ldquoAsymmetric catalysis science and opportunities(nobel lecture)rdquo Angewandte ChemiemdashInternational Editionvol 41 no 12 pp 2008ndash2022 2002

[22] S Borman ldquoAsymmetric catalysis win Chemistry nobel hon-ours knowles noyori sharpless for chiral synthesesrdquo in Chemi-cal amp Engineering News vol 42 pp 5ndash7 2001

[23] J-T Liu and R H Liu ldquoEnantiomeric composition of abusedamine drugs chromatographic methods of analysis and datainterpretationrdquo Journal of Biochemical and Biophysical Methodsvol 54 no 1ndash3 pp 115ndash146 2002

[24] K M Rentsch ldquoThe importance of stereoselective determina-tion of drugs in the clinical laboratoryrdquo Journal of Biochemicaland Biophysical Methods vol 54 no 1ndash3 pp 1ndash9 2002

[25] B G Katzung ldquoThe nature of drugsrdquo in Basic and ClinicalPharmacology Lange Medical Books New York NY USA 9thedition 2006

[26] D Burke and D J Henderson ldquoChirality a blueprint for thefuturerdquo British Journal of Anaesthesia vol 88 no 4 pp 563ndash576 2002

[27] H Y Aboun-Enein and I Ali ldquoIntroductionrdquo in Chiral Separa-tion by Liquid Chromatography and Related Technologies H YAboun-Enein and I Ali Eds pp 1ndash20Mercel Dekker LondonUK 2003

[28] I L Finar ldquoResolution of racemic modificationsrdquo in Stereo-chemistry and the Chemistry of Natural Products vol 2 pp 69ndash119 Longman Harlow UK 6th edition 1996

[29] E Fogassy M Nogradi D Kozma G Egri E Palovics and VKiss ldquoOptical resolution methodsrdquo Organic and BiomolecularChemistry vol 4 no 16 pp 3011ndash3030 2006

[30] J McConathy and M J Owens ldquoStereochemistry in drugactionrdquoThe Primary Care Companion to The Journal of ClinicalPsychiatry vol 5 no 2 pp 70ndash75 2003

[31] K Nomiya and H Yokoyama ldquoSynthesis crystal structuresanti antimicrobial activities of polymeric silver(I) complexeswith three amino-acids [aspartic acid (H2asp) glycine (Hgly)and asparagines (Hasn)]rdquo Journal of Chemical Society DaltonTransaction pp 2483ndash2490 2002

[32] S Saha DDhanasekaran S Chandraleka NThajuddin andAPanneerselvam ldquoSynthesis characterization and antimicrobialactivity of cobalt metal complexes against drug resistant bacte-rial and fungal pathogensrdquo Advances in Biological Research vol4 pp 224ndash229 2010

[33] T O Aiyelabola I A Ojo A C Adebajo et al ldquoSynthesischaracterization and antimicrobial activities of some metal(II)amino acidsrsquo complexesrdquo Advances in Biological Chemistry vol2 pp 268ndash273 2012

[34] S Zhang Y Zhu C Tu et al ldquoA novel cytotoxic ternarycopper(II) complex of 110-phenanthroline and l-threoninewithDNA nuclease activityrdquo Journal of Inorganic Biochemistry vol98 no 12 pp 2099ndash2106 2004

[35] Y-S Kim R Song H C Chung M J Jun and Y S SohnldquoCoordinationmodes vs antitumor activity synthesis and anti-tumor activity of novel platinum(II) complexes ofN-substitutedamino dicarboxylic acidsrdquo Journal of Inorganic Biochemistryvol 98 no 1 pp 98ndash104 2004


[36] S Chanmiya S M Hossain S Easmin M S Islam M AHossain and M Rashid ldquoNew coordination complexes ofchromium as cytotoxic and antimicrobial agentsrdquo PakistanJournal of Biological Science vol 7 no 3 pp 335ndash339 2004

[37] K Bukietynska H Podsiadły and Z Karwecka ldquoComplexes ofvanadium(III) with L-alanine and L-aspartic acidrdquo Journal ofInorganic Biochemistry vol 94 no 4 pp 317ndash325 2003

[38] K Nomiya S Takahashi R Noguchi S Nemoto T Takayamaand M Oda ldquoSynthesis and characterization of water-solublesilver(I) complexes with L-histidine (H2his) and (S)-(-)-2-pyrrolidone-5-carboxylic acid (H2pyrrld) showing a widespectrum of effective antibacterial and antifungal activitiesCrystal structures of chiral helical polymers [Ag(Hhis)]119899 and[Ag(Hpyrrld)]2119899 in the solid staterdquo Inorganic Chemistry vol 39pp 3301ndash3311 2000

[39] R Bregier-Jarzebowska A Gasowska and L Lomozik ldquoCom-plexes of Cu(II) ions and noncovalent interactions in systemswith L-aspartic acid and cytidine-5rsquo-monophosphaterdquo Bioinor-ganic Chemistry and Applications vol 2008 Article ID 25397110 pages 2008

[40] A L Lehninger D L Nelson and M M Cox ldquoAmino acidsbuilding blocks of proteinsrdquo in Principles of Biochemistry W HFreeman Ed pp 71ndash95 CBS New York NY USA 3rd edition2005

[41] A V Legler A S Kazachenko V I Kazbanov O V PerrsquoyanovaandO FVeselova ldquoSynthesis and antimicrobial activity of silvercomplexes with arginine and glutamic acidrdquo PharmaceuticalChemistry Journal vol 35 no 9 pp 501ndash503 2001

[42] T Komiyama S Igarashi and Y Yukawa ldquoSynthesis of polynu-clear complexes with an amino acid or a peptide as a bridgingligandrdquo Current Chemical Biology vol 2 no 2 pp 122ndash1392008

[43] R F See R A Kruse and W M Strub ldquoMetal-ligandbond distances in first-row transition metal coordination com-pounds coordination number oxidation state and specificligand effectsrdquo Inorganic Chemistry vol 37 no 20 pp 5369ndash5375 1998

[44] DA Buckingham ldquoStructure and stereochemistry of coordina-tion compoundsrdquo in Inorganic Biochemistry G Eichhorn Edpp 3ndash61 Elsevier London UK 1973

[45] J J R Frausto da Silva and R J P Williams The BiologicalChemistry of the Elements Oxoford University Press OxfordUK 2nd edition 1984

[46] R H Holm G W Everett and A Chakravorty ldquoMetal com-plexes of schiff bases and120573-ketoaminesrdquo inProgress in InorganicChemistry F A Cotton Ed vol 7 of Progress in InorganicChemistry pp 83ndash214 John Wiley amp Sons Hoboken NJ USA3rd edition 1966

[47] D PMellor ldquoHistorical background and fundamental conceptrdquoin Chelating Agents and Metal Chelate F P Dwyer and DMellor Eds pp 1ndash48 Academic Press New York NY USA1964

[48] V V Glodjovic M D Joksovic and S R Trifunovic ldquoThe geo-metrical isomers of oxalato and malonato-(ethylenediamine-NNrsquo-di-SS-2-propionato)-chromate(III) complexesrdquo Journalof the Serbian Chemical Society vol 70 no 1 pp 1ndash7 2005

[49] Y Moriguchi ldquoTrisethylenediaminecobalt(III)chloride sul-phate as a subject material for widely different chemistry labcoursesrdquo Journal of Chemical Education vol 77 no 8 pp 1045ndash1057 2000

[50] P R Murray E J Baroon M A Pfaller F C Tenover and RH Yolke Manual of Clinical Microbiology vol 6th AmericanSociety for Microbiology Washington DC USA 1995

[51] P N Solis CWWrightMM AndersonM P Gupta and J DPhillipson ldquoAmicrowell cytotoxicity assay using Artemia salina(brine shrimp)rdquo PlantaMedica vol 59 no 3 pp 250ndash252 1993

[52] K Nakamoto ldquoComplexes of amino acidsrdquo in Infrared andRaman Spectra of Inorganic and Coordination Compounds pp66ndash74 Wiley Interscience New York NY USA 6th edition2009

[53] A A Osowole G A Kolawole and O E Fagade ldquoSynthe-sis characterization and biological studies on unsymmetricalSchiff-base complexes of nickel(II) copper(II) and zinc(II) andadducts with 221015840-dipyridine and 110-phenanthrolinerdquo Journalof Coordination Chemistry vol 61 no 7 pp 1046ndash1055 2008

[54] A S Gaballa S M Teleb M S Asker E Yalcin and ZSeferoglu ldquoSynthesis spectroscopic properties and antimicro-bial activity of some new 5-phenylazo-6-aminouracil-vanadylcomplexesrdquo Journal of Coordination Chemistry vol 64 no 24pp 4225ndash4243 2011

[55] D Pavia G Lampman and G Kriz Introduction to Spec-troscopy A Guide for Students of Organic Chemistry Brooks andCole 3rd edition 2001

[56] W Kemp ldquoInfrared spectroscopyrdquo in Organic Spectroscopy pp19ndash98 Macmillan Hong Kong 1991

[57] G L Miessler and D A Tarr ldquoCoordination compoundsrdquo inInorganic Chemistry vol 642 pp 315ndash316 Pearson PrenticeHall New York NY USA 1999

[58] N Juranic B Prelesnik L Manojlovic-Muir K Andjelkovic SR Niketic and M B Celap ldquoGeometrical isomerism of mixedtris(amino carboxylato)cobalt(III) complexes containing glyci-nato and120573-alaninato ligands Crystal structure of trans(O5)-(120573-alaninato)bis(glycinato)cobalt(III) trihydraterdquo Inorganic Chem-istry vol 29 no 8 pp 1491ndash1495 1990

[59] A A Osowole ldquoSynthesis Characterization and Magnetic andThermal Studies on Some Metal(II) Thiophenyl Schiff BaseComplexesrdquo International Journal of Inorganic Chemistry vol2011 Article ID 650186 7 pages 2011

[60] L J Bellamy The Infra-red Spectra of Complex MoleculesSpringer Netherlands 1975

[61] D L Saunders Isolation of lead-amino acid and mercury-amino acid complexes with characterization in the solid state thesolution state and the gas phase [PhD thesis] Department ofChemistry Dalhousie University Halifax Canada 2009

[62] N N Greenwood and A Earnshaw ldquoCoordination com-poundsrdquo in Chemistry of the Elements pp 1290ndash1326 But-terworth-Heinemann Oxford UK 2nd edition 1997

[63] F A Cotton G Wilkinson and C A Murillo AdvancedInorganic Chemistry Wiley Interscience New York NY USA6th edition 1999

[64] N S Youssef and K H Hegab ldquoSynthesis and characterizationof some transition metal complexes of thiosemicarbazonesderived from 2-acetylpyrrole and 2-acetylfuranrdquo Synthesis andReactivity in Inorganic Metal-Organic and Nano-Metal Chem-istry vol 35 no 5 pp 391ndash399 2005

[65] C J Ballhausen An Introduction to Ligand Field TheoryMcGraw Hill New York NY USA 1962

[66] N Raman K Pothiraj and T Baskaran ldquoSynthesis characteri-zation and DNA damaging of bivalent metal complexes incor-porating tetradentate dinitrogen-dioxygen ligand as potentialbiocidal agentsrdquo Journal of Coordination Chemistry vol 64 no24 pp 4286ndash4300 2011


[67] J R Anacona T Martell and I Sanchez ldquoMetal complexesof a new ligand derived from 23-quinoxalinedithiol and 26-bis(bromomethyl)pyridinerdquo Journal of the Chilean ChemicalSociety vol 50 no 1 pp 375ndash378 2005

[68] M P Sathisha V K Revankar and K S R Pai ldquoSynthesisstructure electrochemistry and spectral characterization of bis-isatin thiocarbohydrazone metal complexes and their antitu-mor activity against ehrlich ascites carcinoma in Swiss AlbinomicerdquoMetal-Based Drugs vol 2008 Article ID 362105 11 pages2008

[69] A B P Lever ldquoABP leverrdquo in Inorganic Electronic Spectroscopychapter 4 Elsevier London UK 1986

[70] H C Freeman ldquoMetal complexes of amino acid and peptidesrdquoin Inorganic Biochemistry G Eichhorn Ed pp 121ndash150 Else-vier London UK 1973

[71] R Murray D Granner and V Rodwell ldquoAmino acids andpeptidesrdquo inBiochemistry-Harperrsquos Illustrated P J Kennelly andVW Rodwell Eds pp 77ndash79 Lange Medical Books McGraw-Hill London UK 2006

[72] T O Aiyelabola D A Isabirye E O Akinkunmi O AOgunkunle and I A Ojo ldquoSynthesis characterization andantimicrobial activities of coordination compounds of asparticacidrdquo Journal of Chemistry vol 2016 Article ID 7317015 8 pages2016

[73] L Antolini L Menabue G C Pellacani and G Marcotri-giano ldquoStructural spectroscopic and magnetic properties ofdiaqua(L-aspartato)nickel(II) hydraterdquo Journal of the ChemicalSociety Dalton Transactions no 12 pp 2541ndash2543 1982

[74] G Vuckovic Z Tesic and M Celap ldquoCorrelation between thecomposition and structure of transition metal complexes andtheir Rf valves obtained by planar chromatographyrdquo in Facets ofCoordination Chemistry B Agarwala K N Munsh and A KDale Eds pp 143ndash1191 John Wiley amp Sons Hong Kong 1993

[75] S Prakash Advanced Inorganic Chemistry vol 2 S ChandGroup New Delhi India 2000

[76] V Ujj P Bagi J Schindler J Madarasz E Fogassy and GKeglevich ldquoApractical and efficientmethod for the resolution of3-phospholene 1-oxides via coordination complex formationrdquoChirality vol 22 no 7 pp 699ndash705 2010

[77] S Kirschner N Ahmad C Munir and R J Pollock ldquoThePfeiffer effect outer-sphere complexation and the absoluteconfiguration of dissymmetric coordination compoundsrdquo Pureand Applied Chemistry vol 51 no 4 pp 913ndash923 1979

[78] A Lennartson ldquoOptical resolution and racemisation of[Fe(acac)3]rdquo Inorganica Chimica Acta vol 365 no 1 pp451ndash453 2011

[79] J Lacour and V Hebbe-Viton ldquoRecent developments in chi-ral anion mediated asymmetric chemistryrdquo Chemical SocietyReviews vol 32 no 6 pp 373ndash382 2003

[80] J Lacour and R Frantz ldquoNew chiral anion mediated asymmet-ric chemistryrdquo Organic and Biomolecular Chemistry vol 3 no1 pp 15ndash19 2004

[81] M Fujita and Y Shimura ldquoOptical rotatory dispersion andcircular dichroismrdquo in Spectroscopy and Structure of MetalChelate Compounds K Nakamoto and P J Mccarthy Eds pp201ndash226 Wiley Interscience London UK 2009

[82] M Ibrahim F Wang M-M Lou et al ldquoCopper as anantibacterial agent for human pathogenic multidrug resistantBurkholderia cepacia complex bacteriardquo Journal of Bioscienceand Bioengineering vol 112 no 6 pp 570ndash576 2011

[83] A Abushelaibi Antimicrobial effects of copper and brass ions onthe growth of Listeria monocytogenes at different temperaturespH and nutrients [PhD thesis] Department of Food ScienceAgricultural and Mechanical College Louisiana State Univer-sity Baton Rouge La USA 2005

[84] Centre for Applied Microbiology and Research 2000 httpwwwcopperorgaboutpressreleases2000DemonstratePotentialhtml

[85] Copper Development CentreAntibacterial Properties of Copperand Brass Demonstrate Potential to Combat Toxic Ecoli O157Outbreaks in the Food Processing Industry 2000 httpswwwcopperorgaboutpressreleases2000

[86] Saeed-ur-Rehman M Ikram S Rehman A Faiz and Shah-nawaz ldquoSynthesis characterization and antimicrobial studies oftransition metal complexes of imidazole derivativerdquo Bulletin ofthe Chemical Society of Ethiopia vol 24 no 2 pp 201ndash207 2010

[87] Z H Chohan A Scozzafava and C T Supuran ldquoSynthesisof biologically active Co(II) Cu(II) Ni(II) and Zn(II) com-plexes of symmetrically 111015840-disubstituted ferrocene-derivedcompoundsrdquo Synthesis and Reactivity in Inorganic and Metal-Organic Chemistry vol 33 no 2 pp 241ndash257 2003

[88] Z H Chohan M A Farooq A Scozzafava and C T SupuranldquoAntibacterial schiff bases of oxalyl-hydrazinediamide incor-porating pyrrolyl and salicylyl moieties and of their zinc(II)complexesrdquo Journal of Enzyme Inhibition and Medicinal Chem-istry vol 17 no 1 pp 1ndash7 2002

[89] S Garba and L Salihu ldquoAnAntibacterial activities of 2-O-butyl-1-O-(21015840-ethylhexyl) benzene-18-dicarboxylate and 1-phenyl-14-pentanedione isolated from Vitellaria paradoxa root barkrdquoAsian Journal of Scientific Research vol 4 no 2 pp 149ndash1572011

[90] A Stanila A Marcu D Rusu M Rusu and L David ldquoSpectro-scopic studies of some copper(II) complexes with amino acidsrdquoJournal of Molecular Structure vol 834ndash836 pp 364ndash368 2007

[91] P K Panchal H M Parekh P B Pansuriya and M N PatelldquoBactericidal activity of different oxovanadium(IV) complexeswith Schiff bases and application of chelation theoryrdquo Journal ofEnzyme Inhibition and Medicinal Chemistry vol 21 no 2 pp203ndash209 2006

[92] R S Srivastava ldquoPseudotetrahedral Co(II) Ni(II) and Cu(II)complexes of N1-(O-chlorophenyl)-2-(2101584041015840-dihydroxyphen-yl)-2-benzylazomethine their fungicidal and herbicidal activ-ityrdquo Inorganica Chimica Acta vol 56 pp L65ndashL67 1981

[93] A Prakash and D Adhikari ldquoApplication of Schiff basesand their metal complexes-a reviewrdquo International Journal ofChemTech Research vol 3 no 4 pp 1891ndash1896 2011

[94] C F Carpenter and H F Chambers ldquoDaptomycin anothernovel agent for treating infections due to drug-resistant gram-positive pathogensrdquo Clinical Infectious Diseases vol 38 no 7pp 994ndash1000 2004

[95] D SaıdanaMAMahjoubO Boussaada et al ldquoChemical com-position and antimicrobial activity of volatile compounds ofTamarix boveana (Tamaricaceae)rdquo Microbiological Researchvol 163 no 4 pp 445ndash455 2008

[96] A Olaniyi ldquoPhysico-chemical principles of drug actionrdquo inEssential Medicinal Chemistry pp 29ndash42 Hope PublicationsIbadan Nigeria 2nd edition 2005

[97] A RM Syahmi S Vijayarathna S Sasidharan et al ldquoAcute oraltoxicity and brine shrimp lethality of elaeis guineensis jacq (oilpalm leaf) methanol extractrdquoMolecules vol 15 no 11 pp 8111ndash8121 2010


[98] J R Naidu R Ismail and S Sasidharan ldquoAcute oral toxicity andbrine shrimp lethality of methanol extract ofMentha Spicata L(Lamiaceae)rdquo Tropical Journal of Pharmaceutical Research vol13 no 1 pp 101ndash107 2014

[99] B N Meyer N R Ferrigni J E Putnam L B Jacobsen DE Nichols and J L McLaughlin ldquoBrine shrimp a convenientgeneral bioassay for active plant constituentsrdquo Planta Medicavol 45 no 5 pp 31ndash34 1982

Submit your manuscripts athttpswwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy


Carbohydrate Chemistry

International Journal of


Journal of

Chemistry


Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of


Chromatography Research International


Applied ChemistryJournal of



Theoretical ChemistryJournal of


Journal of

Spectroscopy

Analytical ChemistryInternational Journal of


Journal of


Quantum Chemistry


Organic Chemistry International

ElectrochemistryInternational Journal of



CatalystsJournal of


CH C

O

C

OH

O

+H3N

CH2

Ominus

Figure 1 Aspartic acid

CH C

H

O

Ominus+

NH3

Figure 2 Glycine

that can be considered universal Hence choosing the rightresolving agent for enantiomeric separation may be a her-culean task [13 27]

Previous workers have synthesized and reported somesignificant antimicrobial and cytotoxic activities of coordi-nation compounds of various amino acids [31ndash37] How-ever these studies on their enantiomerically enriched andpure forms are few [38] and as indicated above obtain-ing these compounds at high enantiomeric purity mayenhance their potency and reduce their toxicity Asparticacid (Figure 1) is one of such amino acids studied itpossesses three potential donor sites (one amine and twocarboxyl groups) [37 39 40] It is therefore capable ofcoordinating as a bi- tri- and monodentate and bridgingligand Thus a variety of geometries are possible with thisligand which may be studied by comparing the complexesit forms with a series of metal ions of the same valencyat relevant pH ranges [41ndash47] Hence in this work coor-dination compounds of aspartic acid (L1) and glycine (L2Figure 2) were synthesized and characterized The aspartatocomplexes were synthesized using asymmetric synthesis viachiral pool syntheses while ion exchange chromatographywas used in separating some of the compounds into theirgeometric isomers In determining the most active resolv-ing agent the predominant isomers were further resolvedusing (+)-cis-dichlorobis(ethylenediamine)cobalt(III) chlo-ride (+)-bis(glycinato)(110-phenanthroline)cobalt(III) chlo-ride and (+)-tris(110-phenanthroline)nickel(II) chlorideThe synthesized compounds and resolved complexes werethen screened for their in vitro antimicrobial activity andbrine shrimp lethality

2 Materials and Methods

21 General All reagents and solvents used were of analyticalgrade Melting points or temperatures of decompositionwere measured using open capillary tubes on a Gallenkamp(variable heater)melting point apparatusTheUV-Vis spectra

were obtained using a Genesis 10 UV-Vis spectrophotome-ter at the Central Science Laboratory Obafemi AwolowoUniversity Ile-Ife Nigeria The infrared spectra (KBr) wererecorded on a Genesis II FT-IR spectrophotometer at North-West University Mafikeng Campus South Africa Opticalrotations were measured using Atago Polax-2L polarimeterat the Department of Pharmaceutical Chemistry ObafemiAwolowo University Ile-Ife Magnetic susceptibility wasobtained using a Sherwood scientific balance Kwara StateUniversity Nigeria Antimicrobial activities of the com-plexes was determined at the Department of PharmaceuticsObafemi Awolowo University Ile-Ife Brine shrimp lethalitybioassay was carried out at theDepartment Biochemistry andMolecular Biology Obafemi Awolowo University Ile-Ife

The syntheses characterization and the antimicrobialstudies for the glycinato complexes have been reportedpreviously [33] However the cytotoxic activity is reportedhere for the first time

22 Syntheses of Complexes

221 Preparation Sodium Tris(aspartato)cuprate(II) Na[Cu(L1)3] Copper(II) sulphate anhydrous solution (312 g002M) was dissolved in 10mL of distilled water and warmeduntil a clear solutionwas obtained (+)ndashAspartic acid solution(811 g 006M) was dissolved in distilled water (25mL) andwarmed over a steam bath and Na2SO4 solution (071 g0005M) was added with stirring The copper sulphatesolution was then added and the mixture heated for 2 hourson a steam bath (pH of the reaction was 231) The solutionobtained was concentrated and allowed to cool overnightwith the formation of a precipitate The precipitate obtainedwas filtered washed with methanol and dried in an oven at60∘C Yield 662 g 660 dp 232∘C IR data (cmminus1) 33802922 2851 1666 1547 702 595 UV-Vis data (nm) 217 223238 262 499 517 Magnetic moment 120583eff (BM) 193

Similar methods of preparation were used for the follow-ing compounds

222 Sodium Tris(aspartato)manganese(II) Na[Mn(L1)3]Manganese(II) chloride solution (438 g 002M) was addedto (+)ndashaspartic acid solution (802 g 006M) and sodiumsulphate solution (071 g 0005M) gave sodium tris-asparta-tomanganese(II) as white precipitate pH of reaction 242yield 834 g 830 dp 287∘C IR data (cmminus1) 2920 16811506 779 549 UV-Vis data (nm) 217 259 283 298 550 544574 679 Magnetic moment 120583eff (BM) 530

223 Sodium Tris(aspartato)nickelate(II) Na[Ni(L1)3] Ni-ckel(II) chloride hexahydrate solution (232 g 001M) wasadded to (+)ndashaspartic acid solution (400 g 003M) andsodium chloride solution (058 g 001M) gave sodium tris-aspartatonickelate(II) as fine green crystals pH of reaction237 yield 381 g 8807 dp 265∘C IR data (cmminus1) 34972994 1527 751 595 UV-Vis data (nm) 241 310 325 343 541820 Magnetic moment 120583eff (BM) 283

























(1)

119905119903119886119899119904- [Coen2 (OH)H2O]Cl2 + 2HCl





(+) - [Coen2Cl2]2 [Sb2 (119889-tart)2]


(grind with KCl)

(5)








997888rarr (+) - [Coen2Cl2] (+) - [ML3](6)

































M

O

O

CHC

C

CH

CCH

O

O

O

R

R

O

R

H2N

H2N

NH2







M

NO

OCCH

C

CH

CCH

R

R

R

O

O

OOH2N

NH2

H2

minus





M

N

O

O

OC

CH

C

CH

CCH

OR

R

R

O

O

mer-isomer

M

O

N

O

OC

CH

CH

C

CCH

RR

O

R

O

O

fac-isomer

NH2

H2NH2N

H2

H2

NH2

minusminus













M

N

O

O

OC

CH

C

CH

CCH

OR

R

R

O

O

M

NO

OCCH

C

CH

CCH

R

R

R

O

O

OO

H2N

H2N

H2

H2

NH2

NH2

minusminus









Table3Antim

icrobialactiv

ities

ofthec

ompo

unds

Zone

ofinhibitio

n(sizem

easuredinclu

ded60m

mof

thefi

lterp

aper

disc)

Microorganism

Na[Cu

(L1) 3]

Na[Co(L 1) 3]

Na[Ni(L1) 3]

Na[Co(L 2) 3]

Na[Cd(L 1) 3]

Na[Mn(L 1) 3]

[Cu(L 2) 2]

Acrifl

avine

PR

PR

PR

PR

Ecoli

60

60

60

60

60

80plusmn09

90plusmn03

80plusmn01

60

60

60

200plusmn04

Psaeruginosa

60

60

110plusmn03

80plusmn02

60

60

202plusmn01

240plusmn04

60

80plusmn05

60

60

Pvulga

ris60

60

140plusmn05

60

60

60

90plusmn02

110plusmn06

60

140plusmn08

60

150plusmn06

Saureus

60

160plusmn03

60

120plusmn02

60

60

130plusmn05

60

60

80plusmn01

60

200plusmn02

Bsubtilis

60

60

90plusmn03

180plusmn08

60

60

131plusmn10

160plusmn03

60

80plusmn06

60

60

MRS

A60

60

60

80plusmn04

60

80plusmn05

150plusmn00

160plusmn02

60

200plusmn04

60

60

Calbicans

60

60

18plusmn02

240plusmn05

180plusmn05

90plusmn01

60

60

180plusmn05

60

60

190plusmn01

L 1aspartic

acidL2glycineP

parentcom

poun

dsof

Na[Cu


parent

compo


sE

coliEscherich

iacoliNCT

C8196


aeruginosa

ATCC

19429Pvulga

risP

roteus

vulga

risNCI

BSaureusStaphylo

coccus

aureus

NCT

C6571B

subtilis

BacillussubtilisNCI

B3610M

RSA

methicillin-resis

tant

Saureus

clinicalisolateC

albica

nsC

andida

albicans

NCY

C6












4 Conclusion


Competing Interests


References


















































































































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of

























(1)

119905119903119886119899119904- [Coen2 (OH)H2O]Cl2 + 2HCl





(+) - [Coen2Cl2]2 [Sb2 (119889-tart)2]


(grind with KCl)

(5)








997888rarr (+) - [Coen2Cl2] (+) - [ML3](6)

































M

O

O

CHC

C

CH

CCH

O

O

O

R

R

O

R

H2N

H2N

NH2







M

NO

OCCH

C

CH

CCH

R

R

R

O

O

OOH2N

NH2

H2

minus





M

N

O

O

OC

CH

C

CH

CCH

OR

R

R

O

O

mer-isomer

M

O

N

O

OC

CH

CH

C

CCH

RR

O

R

O

O

fac-isomer

NH2

H2NH2N

H2

H2

NH2

minusminus













M

N

O

O

OC

CH

C

CH

CCH

OR

R

R

O

O

M

NO

OCCH

C

CH

CCH

R

R

R

O

O

OO

H2N

H2N

H2

H2

NH2

NH2

minusminus









Table3Antim

icrobialactiv

ities

ofthec

ompo

unds

Zone

ofinhibitio

n(sizem

easuredinclu

ded60m

mof

thefi

lterp

aper

disc)

Microorganism

Na[Cu

(L1) 3]

Na[Co(L 1) 3]

Na[Ni(L1) 3]

Na[Co(L 2) 3]

Na[Cd(L 1) 3]

Na[Mn(L 1) 3]

[Cu(L 2) 2]

Acrifl

avine

PR

PR

PR

PR

Ecoli

60

60

60

60

60

80plusmn09

90plusmn03

80plusmn01

60

60

60

200plusmn04

Psaeruginosa

60

60

110plusmn03

80plusmn02

60

60

202plusmn01

240plusmn04

60

80plusmn05

60

60

Pvulga

ris60

60

140plusmn05

60

60

60

90plusmn02

110plusmn06

60

140plusmn08

60

150plusmn06

Saureus

60

160plusmn03

60

120plusmn02

60

60

130plusmn05

60

60

80plusmn01

60

200plusmn02

Bsubtilis

60

60

90plusmn03

180plusmn08

60

60

131plusmn10

160plusmn03

60

80plusmn06

60

60

MRS

A60

60

60

80plusmn04

60

80plusmn05

150plusmn00

160plusmn02

60

200plusmn04

60

60

Calbicans

60

60

18plusmn02

240plusmn05

180plusmn05

90plusmn01

60

60

180plusmn05

60

60

190plusmn01

L 1aspartic

acidL2glycineP

parentcom

poun

dsof

Na[Cu


parent

compo


sE

coliEscherich

iacoliNCT

C8196


aeruginosa

ATCC

19429Pvulga

risP

roteus

vulga

risNCI

BSaureusStaphylo

coccus

aureus

NCT

C6571B

subtilis

BacillussubtilisNCI

B3610M

RSA

methicillin-resis

tant

Saureus

clinicalisolateC

albica

nsC

andida

albicans

NCY

C6












4 Conclusion


Competing Interests


References


















































































































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of




997888rarr (+) - [Coen2Cl2] (+) - [ML3](6)

































M

O

O

CHC

C

CH

CCH

O

O

O

R

R

O

R

H2N

H2N

NH2







M

NO

OCCH

C

CH

CCH

R

R

R

O

O

OOH2N

NH2

H2

minus





M

N

O

O

OC

CH

C

CH

CCH

OR

R

R

O

O

mer-isomer

M

O

N

O

OC

CH

CH

C

CCH

RR

O

R

O

O

fac-isomer

NH2

H2NH2N

H2

H2

NH2

minusminus













M

N

O

O

OC

CH

C

CH

CCH

OR

R

R

O

O

M

NO

OCCH

C

CH

CCH

R

R

R

O

O

OO

H2N

H2N

H2

H2

NH2

NH2

minusminus









Table3Antim

icrobialactiv

ities

ofthec

ompo

unds

Zone

ofinhibitio

n(sizem

easuredinclu

ded60m

mof

thefi

lterp

aper

disc)

Microorganism

Na[Cu

(L1) 3]

Na[Co(L 1) 3]

Na[Ni(L1) 3]

Na[Co(L 2) 3]

Na[Cd(L 1) 3]

Na[Mn(L 1) 3]

[Cu(L 2) 2]

Acrifl

avine

PR

PR

PR

PR

Ecoli

60

60

60

60

60

80plusmn09

90plusmn03

80plusmn01

60

60

60

200plusmn04

Psaeruginosa

60

60

110plusmn03

80plusmn02

60

60

202plusmn01

240plusmn04

60

80plusmn05

60

60

Pvulga

ris60

60

140plusmn05

60

60

60

90plusmn02

110plusmn06

60

140plusmn08

60

150plusmn06

Saureus

60

160plusmn03

60

120plusmn02

60

60

130plusmn05

60

60

80plusmn01

60

200plusmn02

Bsubtilis

60

60

90plusmn03

180plusmn08

60

60

131plusmn10

160plusmn03

60

80plusmn06

60

60

MRS

A60

60

60

80plusmn04

60

80plusmn05

150plusmn00

160plusmn02

60

200plusmn04

60

60

Calbicans

60

60

18plusmn02

240plusmn05

180plusmn05

90plusmn01

60

60

180plusmn05

60

60

190plusmn01

L 1aspartic

acidL2glycineP

parentcom

poun

dsof

Na[Cu


parent

compo


sE

coliEscherich

iacoliNCT

C8196


aeruginosa

ATCC

19429Pvulga

risP

roteus

vulga

risNCI

BSaureusStaphylo

coccus

aureus

NCT

C6571B

subtilis

BacillussubtilisNCI

B3610M

RSA

methicillin-resis

tant

Saureus

clinicalisolateC

albica

nsC

andida

albicans

NCY

C6












4 Conclusion


Competing Interests


References


















































































































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of
















M

O

O

CHC

C

CH

CCH

O

O

O

R

R

O

R

H2N

H2N

NH2







M

NO

OCCH

C

CH

CCH

R

R

R

O

O

OOH2N

NH2

H2

minus





M

N

O

O

OC

CH

C

CH

CCH

OR

R

R

O

O

mer-isomer

M

O

N

O

OC

CH

CH

C

CCH

RR

O

R

O

O

fac-isomer

NH2

H2NH2N

H2

H2

NH2

minusminus













M

N

O

O

OC

CH

C

CH

CCH

OR

R

R

O

O

M

NO

OCCH

C

CH

CCH

R

R

R

O

O

OO

H2N

H2N

H2

H2

NH2

NH2

minusminus









Table3Antim

icrobialactiv

ities

ofthec

ompo

unds

Zone

ofinhibitio

n(sizem

easuredinclu

ded60m

mof

thefi

lterp

aper

disc)

Microorganism

Na[Cu

(L1) 3]

Na[Co(L 1) 3]

Na[Ni(L1) 3]

Na[Co(L 2) 3]

Na[Cd(L 1) 3]

Na[Mn(L 1) 3]

[Cu(L 2) 2]

Acrifl

avine

PR

PR

PR

PR

Ecoli

60

60

60

60

60

80plusmn09

90plusmn03

80plusmn01

60

60

60

200plusmn04

Psaeruginosa

60

60

110plusmn03

80plusmn02

60

60

202plusmn01

240plusmn04

60

80plusmn05

60

60

Pvulga

ris60

60

140plusmn05

60

60

60

90plusmn02

110plusmn06

60

140plusmn08

60

150plusmn06

Saureus

60

160plusmn03

60

120plusmn02

60

60

130plusmn05

60

60

80plusmn01

60

200plusmn02

Bsubtilis

60

60

90plusmn03

180plusmn08

60

60

131plusmn10

160plusmn03

60

80plusmn06

60

60

MRS

A60

60

60

80plusmn04

60

80plusmn05

150plusmn00

160plusmn02

60

200plusmn04

60

60

Calbicans

60

60

18plusmn02

240plusmn05

180plusmn05

90plusmn01

60

60

180plusmn05

60

60

190plusmn01

L 1aspartic

acidL2glycineP

parentcom

poun

dsof

Na[Cu


parent

compo


sE

coliEscherich

iacoliNCT

C8196


aeruginosa

ATCC

19429Pvulga

risP

roteus

vulga

risNCI

BSaureusStaphylo

coccus

aureus

NCT

C6571B

subtilis

BacillussubtilisNCI

B3610M

RSA

methicillin-resis

tant

Saureus

clinicalisolateC

albica

nsC

andida

albicans

NCY

C6












4 Conclusion


Competing Interests


References


















































































































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


M

N

O

O

OC

CH

C

CH

CCH

OR

R

R

O

O

mer-isomer

M

O

N

O

OC

CH

CH

C

CCH

RR

O

R

O

O

fac-isomer

NH2

H2NH2N

H2

H2

NH2

minusminus













M

N

O

O

OC

CH

C

CH

CCH

OR

R

R

O

O

M

NO

OCCH

C

CH

CCH

R

R

R

O

O

OO

H2N

H2N

H2

H2

NH2

NH2

minusminus









Table3Antim

icrobialactiv

ities

ofthec

ompo

unds

Zone

ofinhibitio

n(sizem

easuredinclu

ded60m

mof

thefi

lterp

aper

disc)

Microorganism

Na[Cu

(L1) 3]

Na[Co(L 1) 3]

Na[Ni(L1) 3]

Na[Co(L 2) 3]

Na[Cd(L 1) 3]

Na[Mn(L 1) 3]

[Cu(L 2) 2]

Acrifl

avine

PR

PR

PR

PR

Ecoli

60

60

60

60

60

80plusmn09

90plusmn03

80plusmn01

60

60

60

200plusmn04

Psaeruginosa

60

60

110plusmn03

80plusmn02

60

60

202plusmn01

240plusmn04

60

80plusmn05

60

60

Pvulga

ris60

60

140plusmn05

60

60

60

90plusmn02

110plusmn06

60

140plusmn08

60

150plusmn06

Saureus

60

160plusmn03

60

120plusmn02

60

60

130plusmn05

60

60

80plusmn01

60

200plusmn02

Bsubtilis

60

60

90plusmn03

180plusmn08

60

60

131plusmn10

160plusmn03

60

80plusmn06

60

60

MRS

A60

60

60

80plusmn04

60

80plusmn05

150plusmn00

160plusmn02

60

200plusmn04

60

60

Calbicans

60

60

18plusmn02

240plusmn05

180plusmn05

90plusmn01

60

60

180plusmn05

60

60

190plusmn01

L 1aspartic

acidL2glycineP

parentcom

poun

dsof

Na[Cu


parent

compo


sE

coliEscherich

iacoliNCT

C8196


aeruginosa

ATCC

19429Pvulga

risP

roteus

vulga

risNCI

BSaureusStaphylo

coccus

aureus

NCT

C6571B

subtilis

BacillussubtilisNCI

B3610M

RSA

methicillin-resis

tant

Saureus

clinicalisolateC

albica

nsC

andida

albicans

NCY

C6












4 Conclusion


Competing Interests


References


















































































































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


M

N

O

O

OC

CH

C

CH

CCH

OR

R

R

O

O

M

NO

OCCH

C

CH

CCH

R

R

R

O

O

OO

H2N

H2N

H2

H2

NH2

NH2

minusminus









Table3Antim

icrobialactiv

ities

ofthec

ompo

unds

Zone

ofinhibitio

n(sizem

easuredinclu

ded60m

mof

thefi

lterp

aper

disc)

Microorganism

Na[Cu

(L1) 3]

Na[Co(L 1) 3]

Na[Ni(L1) 3]

Na[Co(L 2) 3]

Na[Cd(L 1) 3]

Na[Mn(L 1) 3]

[Cu(L 2) 2]

Acrifl

avine

PR

PR

PR

PR

Ecoli

60

60

60

60

60

80plusmn09

90plusmn03

80plusmn01

60

60

60

200plusmn04

Psaeruginosa

60

60

110plusmn03

80plusmn02

60

60

202plusmn01

240plusmn04

60

80plusmn05

60

60

Pvulga

ris60

60

140plusmn05

60

60

60

90plusmn02

110plusmn06

60

140plusmn08

60

150plusmn06

Saureus

60

160plusmn03

60

120plusmn02

60

60

130plusmn05

60

60

80plusmn01

60

200plusmn02

Bsubtilis

60

60

90plusmn03

180plusmn08

60

60

131plusmn10

160plusmn03

60

80plusmn06

60

60

MRS

A60

60

60

80plusmn04

60

80plusmn05

150plusmn00

160plusmn02

60

200plusmn04

60

60

Calbicans

60

60

18plusmn02

240plusmn05

180plusmn05

90plusmn01

60

60

180plusmn05

60

60

190plusmn01

L 1aspartic

acidL2glycineP

parentcom

poun

dsof

Na[Cu


parent

compo


sE

coliEscherich

iacoliNCT

C8196


aeruginosa

ATCC

19429Pvulga

risP

roteus

vulga

risNCI

BSaureusStaphylo

coccus

aureus

NCT

C6571B

subtilis

BacillussubtilisNCI

B3610M

RSA

methicillin-resis

tant

Saureus

clinicalisolateC

albica

nsC

andida

albicans

NCY

C6












4 Conclusion


Competing Interests


References


















































































































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


Table3Antim

icrobialactiv

ities

ofthec

ompo

unds

Zone

ofinhibitio

n(sizem

easuredinclu

ded60m

mof

thefi

lterp

aper

disc)

Microorganism

Na[Cu

(L1) 3]

Na[Co(L 1) 3]

Na[Ni(L1) 3]

Na[Co(L 2) 3]

Na[Cd(L 1) 3]

Na[Mn(L 1) 3]

[Cu(L 2) 2]

Acrifl

avine

PR

PR

PR

PR

Ecoli

60

60

60

60

60

80plusmn09

90plusmn03

80plusmn01

60

60

60

200plusmn04

Psaeruginosa

60

60

110plusmn03

80plusmn02

60

60

202plusmn01

240plusmn04

60

80plusmn05

60

60

Pvulga

ris60

60

140plusmn05

60

60

60

90plusmn02

110plusmn06

60

140plusmn08

60

150plusmn06

Saureus

60

160plusmn03

60

120plusmn02

60

60

130plusmn05

60

60

80plusmn01

60

200plusmn02

Bsubtilis

60

60

90plusmn03

180plusmn08

60

60

131plusmn10

160plusmn03

60

80plusmn06

60

60

MRS

A60

60

60

80plusmn04

60

80plusmn05

150plusmn00

160plusmn02

60

200plusmn04

60

60

Calbicans

60

60

18plusmn02

240plusmn05

180plusmn05

90plusmn01

60

60

180plusmn05

60

60

190plusmn01

L 1aspartic

acidL2glycineP

parentcom

poun

dsof

Na[Cu


parent

compo


sE

coliEscherich

iacoliNCT

C8196


aeruginosa

ATCC

19429Pvulga

risP

roteus

vulga

risNCI

BSaureusStaphylo

coccus

aureus

NCT

C6571B

subtilis

BacillussubtilisNCI

B3610M

RSA

methicillin-resis

tant

Saureus

clinicalisolateC

albica

nsC

andida

albicans

NCY

C6












4 Conclusion


Competing Interests


References


















































































































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of












4 Conclusion


Competing Interests


References


















































































































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of

















































































































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of

syntheses, characterization, resolution, and biological...

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